Brake mechanism



Feb. 16, 1937. J. SNEED BRAKE MECHANISM 2 Sheets-Sheet 1 Filed June 18, 1928 F IG. 1

J. SNEED 2,071,144

BRAKE MECHANI SM- Feb. 16, 1937.

2 Sheets-Sheet 2 Filed June 18, 1923 A Patented Feb. 16, 1937 V a morjIANis'M v .John Sneed;;.Ferndale, Mihmatssignor to The Midland"Steel-Products,=:Company, Cleveland, Ohio, a corppration of Ohio a ApplicationpJune 18f. 192 8, Sl 1:ia l No. 286,155

' .2 Claims. (Cl .188+-78) Thisinvention relates to' brakes andmore particularly to adevice for actuating the brake along withthe shoe construction and arrangementof cooperating parts. i I a "It, is among the objects of my invention to provide a device for spreading the ends, of a full fioatingbrake shoe apart while either ofthe ends remains in a fixed position. A further object vis to arrange a spreading mechanism which may be journalled in a fixed bearing but whichwill deliver force and motion in either of two direc' tions. A furtherobj'ect is to arrange thrust parts for'transinittin'gjthe spreading force'toithe shoe.

Another object is to providea full floating shoe .anchorable I adjacent ,the expanding device and adjustablypositioned Within the brake drum. A furtherI. object is to arrange 'a shoe cooperable with thef expanding' device to form a, self-: energizing brake with parts arranged to prevent grabbing. v

Other objects include the provision of suitable retractor springs, adjusting shoe positioning means which will appear from the following description of a preferred form of my invention, reference being had to the accompanying drawings. The essential characteristics are summarized in the claims.

Fig. l is. a partially broken elevation of the brake assembly including the expanding device; Fig. 2 is a section taken along the line 2-2 of Fig. 1; Fig. 3 is a section taken along the line 3-3 of Fig. 1, and Fig. 4 illustrates a modified form of the expanding device.

Referring particularly to Fig. 1, I show a brake having a drum D and an apron or backing plate A which carries an anchor pin P. A full floating shoe S comprising a relatively flexible band-like part I Welded to a relatively rigid channeled part 2 as at 3, anchors at either end along arcuate anchor engaging surfaces 4 and 5. The channel part of the shoe may be of substantially uniform depth and comprise the "served part of the shoe when the drum rotates counter-clockwise, as indicated. Suitable brake lining L is carried by the shoe. A separate thrust member I0 is adjustably secured to the flexible end of the shoe in a retaining member I by such means as a clamp bolt I2, as described in my copending application Serial No. 281,062 filed May 28th, 1928. The thrust member I0 and the channel end of the shoe carry laterally extending pins I3 and I4, see also Fig. 3, against which the expanding device acts.

\ Referring also to Fig. 1, the shoe is centered within the drum and retracted from, engagement therewith by retractor springs I5 and |6,.which draw the ends of the shoe ontothe anchor. The spring I6 may be stronger so that in the usual application of the brake when the drum is rotating counter-clockwise, the band-like end of the 5 shoe is first thrust into engagement with the 'An adjustable eccentric stop I1 engages 'the end'of the channel section of. the shoe adjac ent the joint with the band-like section and';a..spring I8 draws the channel part of theshoe against the adjustable stop and holds it there in idle position. The spring I8 has oneiend conne ctedxto the outer side flange of the channel part. as at I9 and has its otherend connected to the apron as at so that the mid-portion of the whole shoeis drawn against the apron. The apron has raised portions as at 2| and 22 which .are spa'cedapart and whichsupport theflmid-portion ofthejshoe at spaced. points and hold the body of thelshoe 20 away from thejapron, Referring also to Fig. 3', it will be seen that thesprings I5 and I6 extend at an angle to the apron and tend to draw the ends of the shoe toward the apron. The ends of the shoe are spaced from the apron by the ends of 25 the pins I3 and I4 which contact with the apron as at 23.

Having described a preferred form of the general brake structure and arrangement, I will now describe the expanding mechanism, reference being had particularly to Figs. 1 and 3. Journalled in the apron and in a bracket B is a shaft 30 to which is pinned or clamped an arm 3|. The arm 3| may be connected with means not shown for rotating the shaft by any one of the several well known means. To operate the expanding device the shaft is rotated clockwise as viewed in Fig. 1. The shaft may be held against longitudinal movement between a shoulder 32 and the end of the arm 3|. Integrally formed or otherwise secured to the shaft is an enlarged head 33 which, near its ends, carries pins 34 and 35. Pivotally mounted on these pins are arms and 4| which I arms are interconnected through gearing as at 42. The arm 40 engages the pin I3 which is carried by the member I0 at one end of the shoe, and the arm 4| engages the pin I4 which is carried by the flanges of the channel at the other end of the shoe. Rotation of the shaft 30 in a clockwise direction moves the pins 34 and 35 clockwise and tends to spread the arms 40 and 4|.

If the rotation of the drum be counter-clockwise the channel end of the shoe will be held against the anchor by the braking torque, and

it is my desire that all of the motion from the free end of the shoe into engagement with the drum.

When the drum is rotating in the reverse di-;

rection, then the pin l3 will be held in relatively fixed position by the braking torque and clockwise rotation of the shaft 30 will cause the arm 4| to move the pin I4 and force the other end of the shoe into engagement with thedrum.

As appears in Fig. 1, the pin I4 is ata higher elevation than the pin l3 and it may be observed that in the usual application of the brake when the vehicle moves forwardly, that the arm 40 exerts a force which has an upwardly acting vertical component which tends to raise the free end of the shoe into engagement with the drum as well as move it away from the anchor pin.

In Fig. 4 is illustrated a modified form of my invention wherein the arms 40A and MA correspond to the arms 40 and 4| and may be pivoted about pins 34A and 35A. In this modification instead of gearing the arms together, they are formed to contact with each other along contacting surfaces as at 42A and react upon each other in a like manner. Force and motion are delivered to pins |3A and MA with substantially the same effect as if the arms were geared together. I

It will appear from the foregoing that I have provided a complete brake and expansion device for operating the brake shoe, which will force either end of the shoe into engagement with the drum while the other end of the shoe is held in contact with the anchor. Various modifications may occur tothose skilled in the art all within the major precepts of my invention but I do not care to be limited to the particular form of my invention illustrated and described herewith, or in any manner, other than by the claims appended hereto.

I claim:

1. An expanding device for a brake having friction parts and adapted to deliver compressive forces in opposite directions and move in at least one direction, said device comprising a rotatable member having arms pivoted at itsends, said arms carrying interfitting gear segments meshing substantially in line with the points of pivotal mounting-said arms extended parallel and in opposite directions from the said points and engaging 'the friction part of the brake at' their ends,the point of engagement of each of said arms being substantially at the same elevation as the points of pivotal mounting forthe other of said arms whereby rotation of said member moves at least one of said friction parts.

2. An expanding device for a brake shoe adapted todeliver compressive forces in opposite directions and move in at least one direction, said device comprising a member rotatable about a fixed axis and having arms pivoted at its ends, said arms carrying interfltting gear segments meshing substantially in line with the points of pivotal mounting, said arms extending parallel and in opposite directions from the said points and engaging adjacent ends of the brake shoe at the ends of the arms, the point of engagement of one of said arms being below the said axis whereby rotation of said member causes the end of that arm to raise the adjacent end of the shoe as it moves that end of the shoe into engagement with the drum.

JOHN SNEED. 

